The modification of engine control units to disable diesel particulate filters (DPF) and exhaust gas recirculation (EGR) systems involves specialized programming. This process alters the software that governs engine operation, effectively preventing these emission control devices from functioning as intended. For example, a modified engine control unit might ignore signals from DPF sensors, preventing regeneration cycles and associated error codes.
Circumventing factory-installed emission controls can potentially offer performance gains and reduced maintenance costs. Historically, this practice has been pursued to address issues such as DPF clogging and EGR valve malfunction, particularly in vehicles operating under demanding conditions. However, the long-term environmental impact and legal implications must be carefully considered.